Five Questions to Ask Before Starting Pembrolizumab

Starting a new cancer treatment is a significant decision. Asking the right questions before you commit ensures you understand what you are agreeing to - and helps you decide whether this is the right path for your situation. Here are five questions that matter, and what honest answers to them should look like.

1. Am I eligible based on my specific cancer and PD-L1 result?

This is the most fundamental question. Pembrolizumab is not appropriate for every cancer type or every PD-L1 result. A good clinical team will explain specifically why you qualify based on your cancer type, your PD-L1 TPS or CPS score, your treatment history, and any relevant biomarkers such as EGFR mutation status or MSI-H. If you are told you are eligible without this level of specificity, push for more detail.

2. What side effects are most likely for me specifically?

The general side effect profile of pembrolizumab is well established. But your individual risk profile depends on factors including your age, any underlying conditions, your performance status, and the specific cancer you have. Ask your oncologist: given my particular situation, which immune-related adverse events should I be most alert to, and at what point should I contact you? A thoughtful answer will be specific to your circumstances, not a recitation of the general package insert.

3. How will we monitor my response - and what are we looking for?

Monitoring during pembrolizumab has two purposes: detecting treatment-related side effects early, and assessing whether the treatment is working. Ask which blood tests will be done and how often, what imaging will be used to assess response, and what the criteria are for continuing, pausing, or stopping treatment. Understanding the monitoring plan upfront helps you interpret results when they come back.

4. What happens if I have a significant immune reaction at home?

This is particularly important for home-based treatment. Ask: what is the escalation pathway if I develop symptoms of a serious irAE? Who do I call, at what time of day, and what happens next? A responsible home treatment programme will have clear, documented protocols for this - including 24-hour access to clinical advice and defined criteria for what requires urgent assessment. If this is not immediately clear, it should be before treatment starts.

5. What does the treatment cost and exactly what is included?

Pembrolizumab is expensive, and private treatment adds costs for the drug, nursing, monitoring, and clinical oversight. Ask for a complete breakdown: what is included in the quoted price, what costs might arise additionally (such as extra blood tests or additional visits), and what happens to costs if treatment needs to be modified or stopped. A transparent provider will give you a clear, written cost structure before any commitment is made.